Patent Document No. 1 teaches a displacement control valve of a variable displacement compressor for opening and closing a communication passage extending between a portion of the compressor on which discharge pressure acts and a crank chamber of the compressor, thereby controlling the displacement of the compressor, comprising a valve hole communicating with the crank chamber at one end and opening to a valve chamber at the other end, a valve body for opening and closing the valve hole at one end located in the valve chamber communicating with the portion of the compressor on which discharge pressure acts, a bulkhead provided with a supporting hole for slidably supporting the valve body and shutting the other end of the valve body off from the valve chamber, a pressure inlet passage for allowing crank chamber pressure to act on the other end of the valve body, and a driver for driving the valve body in a direction for opening and closing the valve hole.
The displacement control valve taught by Patent Document No. 1 has an advantage in that discharge chamber pressure does not act on the valve body in the direction for opening and closing the valve hole.    Patent Document No. 1: Japanese Patent Laid-Open Publication No. 11-107929